A method and device for on-demand connection of quantum bits in an atomic array

Abstract

The present application discloses a method and device for on-demand connection of quantum bits in an atomic array, comprising the following steps: obtaining a low-temperature, low-speed cold atomic cluster using a magneto-optical trap system; forming a two-dimensional dipole trap array after strong focusing of a beam of dipole light to load atoms to form a quantum bit array; generating a mobile trap using another position-controlled dipole light and moving it in the two-dimensional dipole trap array to transfer atoms from a single trap in the two-dimensional dipole trap array and move the atoms with the mobile trap; wherein the two-dimensional dipole trap array and the mobile trap are both under magic light intensity conditions, and when the mobile trap moves the atoms in a single trap of the two-dimensional dipole trap array to a distance between the atoms and the atoms in another single trap that meets the Rydberg blockade requirement, the Rydberg excitation light is simultaneously applied to the two atoms to achieve long-distance on-demand connection of any two atoms in the two-dimensional dipole trap array.

Description

Technical Field

[0001] The present application relates to the field of quantum computing technology, and in particular to a method and device for on-demand connection of quantum bits in an atomic array. Background Art

[0002] Universal quantum computing requires a certain number of qubits. The scalability of qubits in neutral atom systems can be achieved through optical dipole trap arrays. Performing two-qubit gate manipulation in atomic arrays generally requires strong Rydberg interactions between atoms, which typically require interatomic distances within a few microns. Large-scale atomic arrays can reach tens or even hundreds of microns in size. In this case, atoms only interact with their immediate neighbors, and two-qubit gate manipulation is limited to these neighbors. This results in low connectivity between qubits in the array, affecting the efficiency of quantum circuit execution and failing to fully exploit the scalability of neutral atom systems. Improving the connectivity between neutral atom qubits and enabling on-demand connection between qubits is a critical issue that needs to be addressed for the further development of this system. Summary of the Invention

[0003] The present invention provides a method and apparatus for connecting qubits on demand in an atomic array. This method can connect any two atoms in the atomic array and flexibly select the connection method between atoms according to the requirements of the quantum algorithm to achieve the purpose of on-demand connection. The technical solution is as follows:

[0004] In a first aspect, the present application provides a method for on-demand connection of quantum bits in an atomic array, comprising the following steps: obtaining a low-temperature, low-speed cold atomic cluster using a magneto-optical trap system; forming a two-dimensional dipole trap array by strongly focusing a beam of dipole light, wherein the focus of the two-dimensional dipole trap array coincides with the center of the cold atomic cluster, so as to load atoms to form a quantum bit array; generating a mobile trap by another position-controlled dipole light and moving it in the two-dimensional dipole trap array, so as to transfer atoms from a single trap in the two-dimensional dipole trap array and move them with the mobile trap; wherein the two-dimensional dipole trap array and the mobile trap are both under magic light intensity conditions, and when the mobile trap moves the atoms in a single trap of the two-dimensional dipole trap array to a distance between the atoms in another single trap and the atoms in the other single trap that meets the Rydberg blockade requirement, Rydberg excitation light is simultaneously applied to the two atoms to realize a two-bit controlled phase gate; and then the moved atoms are moved back to their original positions by the mobile trap to realize long-distance on-demand connection of any two atoms in the two-dimensional dipole trap array.

[0005] For example, in a method for on-demand connection of quantum bits in an atomic array provided by one embodiment, the power of the mobile well is twice the power of the two-dimensional dipole well array.

[0006] For example, in a method for on-demand connection of quantum bits in an atomic array provided in one embodiment, the dipole light generated by the mobile trap is focused on the two-dimensional dipole trap array after passing through an acousto-optic deflector, and the angle of the outgoing light is changed by changing the frequency of the radio frequency signal input to the acousto-optic deflector, so that the light can be moved in the two-dimensional dipole trap array.

[0007] For example, in a method for on-demand connection of quantum bits in an atomic array provided in one embodiment, the radio frequency coordinates corresponding to each grid point in the two-dimensional dipole trap array are calibrated, and the radio frequency waveform of the mobile trap is set so that the mobile trap traverses the position of each trap in the two-dimensional dipole trap array.

[0008] For example, in a method for on-demand connection of quantum bits in an atomic array provided in one embodiment, atoms are loaded into the two-dimensional dipole well array through a random loading process, and then fluorescence imaging is used to determine whether atoms are loaded in each individual well of the two-dimensional dipole well array.

[0009] The second aspect of the present application provides a device for on-demand connection of quantum bits in an atomic array, including a magneto-optical trap system for generating low-temperature and low-speed cold atomic clusters; a spatial light modulator, a beam combiner, a first filter, a first strong focusing lens and a first quantized magnetic field coil are sequentially arranged on one side of the magneto-optical trap system and along the central axis of the magneto-optical trap system, and a second quantized magnetic field coil, a second strong focusing lens, a second filter and a CCD camera are sequentially arranged on the other side of the magneto-optical trap system and along the central axis of the magneto-optical trap system; wherein a beam of dipole light is transmitted to the spatial light modulator, reflected by the spatial light modulator and then transmitted to the beam combiner, then transmitted through the first filter, and then transmitted by the first strong focusing lens. After focusing, the focusing lens forms the two-dimensional dipole trap array and the focus coincides with the cold atomic cluster in the magneto-optical trap system; after another beam of dipole light is diffracted by the acousto-optic deflector, the diffracted light is incident on the beam combiner, and the light reflected by the beam combiner passes through the first filter and is transmitted. After the transmission, the light is focused by the first strong focusing lens and the focus falls on the focal plane of the two-dimensional dipole trap array; the first Rydberg excitation light is reflected by the first filter and focused by the first strong focusing lens and the focus falls on the focal plane of the two-dimensional dipole trap array; the second Rydberg excitation light is reflected by the second filter and focused by the second strong focusing lens and the focus falls in reverse on the focal plane of the two-dimensional dipole trap array.

[0010] For example, in a device for on-demand connection of quantum bits in an atomic array provided in one embodiment, the magneto-optical trap system includes a vacuum cavity, a pair of anti-Helmholtz coils are provided at the center of the vacuum cavity to form a gradient magnetic field with increasing magnetic field intensity from the center of the anti-Helmholtz coils toward the outside; three pairs of cooling lights are provided in the vacuum cavity to subject atoms to radiation pressure along the propagation direction of the cooling light, and to cause the atoms in the vacuum cavity to form a low-temperature and low-speed cold atomic cluster and gather at the center of the gradient magnetic field.

[0011] For example, in a device for on-demand connection of quantum bits in an atomic array provided in one embodiment, the three pairs of cooling lights are 780nm wavelength lasers propagating in opposite directions. The cooling lights subject the atoms to radiation pressure along the propagation direction of the cooling lights, causing the atoms to slow down and form optical clumps.

[0012] For example, in a device for on-demand connection of quantum bits in an atomic array provided in one embodiment, one beam of dipole light is transmitted to a first fiber coupling frame via an optical fiber, and the light output by the first fiber coupling frame is transmitted to the spatial light modulator; the other beam of dipole light is transmitted to a second fiber coupling frame via an optical fiber, and the light output by the second fiber coupling frame is incident on the combiner after being diffracted by the acousto-optic deflector. The incident angle of the light spot is shifted by changing the frequency of the radio frequency signal of the acousto-optic deflector, and the movable trap is moved on the focal plane of the two-dimensional dipole trap array.

[0013] For example, in a device for on-demand connection of quantum bits in an atomic array provided in one embodiment, the spatial light modulator is connected to a host, and a GS algorithm is run on the host to generate a phase diagram, so that the spatial light modulator modulates the phase of the beam of dipole light, and forms a two-dimensional dipole well array after the beam of dipole light is strongly focused by the first strong focusing lens.

[0014] The beneficial effects brought about by a method and device for on-demand connection of quantum bits in an atomic array provided in some embodiments of the present application are as follows: the present application utilizes a method of matching a two-dimensional dipole trap array and a mobile trap under magic light intensity conditions to achieve the connection between any two atoms in the two-dimensional dipole trap array, and flexibly selects the connection method between atoms according to the requirements of the quantum algorithm to achieve the purpose of on-demand connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a schematic diagram of the overall structure of the on-demand quantum bit connection device in the atomic array of the present application;

[0017] Figure 2 Schematic diagram of the two-dimensional dipole trap array structure of the present application;

[0018] Figure 3 is a graph showing the relationship between the power ratio of the mobile trap and the two-dimensional dipole trap array and the transfer efficiency of the present application;

[0019] Figure 4 is a graph showing the relationship between the differential optical frequency shift and the power of the two-dimensional dipole trap array of the present application;

[0020] Figure 5 This is a schematic diagram of the on-demand connection of quantum bits in the atomic array of this application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0022] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] This application provides a device for connecting quantum bits on demand in an atomic array, such as Figure 1As shown, it includes a magneto-optical trap system 1 for generating low-temperature and low-speed cold atomic groups; a spatial light modulator 2, a beam combiner 3, a first filter 41, a first strong focusing lens 51 and a first quantized magnetic field coil 61 are sequentially provided on one side of the magneto-optical trap system 1 and along the central axis of the magneto-optical trap system 1; a second quantized magnetic field coil 62, a second strong focusing lens 52, a second filter 42 and a CCD camera 7 are sequentially provided on the other side of the magneto-optical trap system 1 and along the central axis of the magneto-optical trap system 1;

[0024] Among them, a beam of dipole light, recorded as the first dipole light 81, is transmitted to the first fiber coupling frame 811 through the optical fiber, and the light output by the first fiber coupling frame 811 is transmitted to the spatial light modulator 2, and is transmitted to the combiner after being reflected by the spatial light modulator 2. Most of the light is transmitted through the combiner 3, and then transmitted through the first filter 41. It is then focused by the first strong focusing lens 51 to form a two-dimensional dipole trap array, and the focus coincides with the cold atomic group in the magneto-optical trap system 1. The spatial light modulator 2 is connected to the host 21, and the GS algorithm is run on the host 21 to generate a phase diagram, so that the spatial light modulator 2 modulates the phase of the beam of dipole light, i.e., the first dipole light 81, and forms a two-dimensional dipole trap array after being strongly focused by the first strong focusing lens 51, as shown in FIG. Figure 2 As shown, Figure 2 A 4×4 two-dimensional dipole trap array formed by a spatial light modulator 2 is presented, in which each grid point can be used to load a single atom.

[0025] Another beam of dipole light, recorded as the second dipole light 82, is transmitted through the optical fiber to the second optical fiber coupling frame 822, and the light output by the second optical fiber coupling frame 822 is diffracted by the acousto-optic deflector 9 and then incident on the combiner 3. The diffracted light is incident on the combiner 3, and part of the light will be reflected. Then, the light reflected by the combiner 3 passes through the first filter 41 and is transmitted. After transmission, the light is focused by the first strong focusing lens 51 and the focus falls on the focal plane of the two-dimensional dipole trap array. By changing the RF signal frequency of the acousto-optic deflector 9 to achieve the offset of the light spot incident angle, the focused light spot of the second dipole light 82 is moved on the focal plane of the two-dimensional dipole trap array, and the focused light spot of the second dipole light 82 is the moving trap.

[0026] The first Rydberg excitation light A is reflected by the first filter 41 and focused by the first strong focusing lens 51, and the focus falls on the focal plane of the two-dimensional dipole trap array; the second Rydberg excitation light B is reflected by the second filter 42 and focused by the second strong focusing lens 52, and the focus falls in reverse on the focal plane of the two-dimensional dipole trap array.

[0027] The first Rydberg excitation light A and the second Rydberg excitation light B are both transmitted through optical fibers to their respective fiber coupling mounts for emission, and then reflected by filters. The propagation direction of the first Rydberg excitation light A is the same as that of the dipole light. After being focused by the first strong focusing lens 51, the focus falls on the focal plane of the two-dimensional dipole well array. The propagation direction of the second Rydberg excitation light B is opposite to that of the dipole light. After being focused by the second strong focusing lens 52, the focus also falls on the focal plane of the two-dimensional dipole well array.

[0028] The CCD (Charge coupled Device) camera is used to observe the two-dimensional dipole well array at the focus, and determine whether each single well of the two-dimensional dipole well array is loaded with atoms through fluorescence imaging.

[0029] The first quantized magnetic field coil 61 and the second quantized magnetic field coil 62 are a pair of Helmholtz coils, which can be used to generate a uniform magnetic field by applying current to the coils. The magnetic field is along the propagation direction of the dipole light, and the center position of the coil is at the focus position of the dipole trap.

[0030] For example, in an embodiment of the invention, in a device for connecting quantum bits on demand in an atomic array, as shown in FIG. Figure 1 As shown, the magneto-optical trap system 1 includes a vacuum chamber 11, and a pair of anti-Helmholtz coils 12 are provided at the center of the vacuum chamber 11 to form a gradient magnetic field with increasing magnetic field strength from the center of the anti-Helmholtz coils 12 to the outside; three pairs of cooling lights 13 are provided in the vacuum chamber 11 to subject atoms to radiation pressure along the propagation direction of the cooling lights 13, and to cause the atoms in the vacuum chamber 11 to form low-temperature and low-speed cold atomic clusters that gather at the center of the gradient magnetic field.

[0031] For example, in a device for on-demand connection of quantum bits in an atomic array provided in one embodiment, the three pairs of cooling lights 13 are respectively 780nm wavelength lasers propagating in opposite directions. The cooling lights 13 subject the atoms to radiation pressure along the propagation direction of the cooling lights 13, causing the atoms to slow down and form optical clumps.

[0032] Specifically, the anti-Helmholtz coil 12 forms a gradient magnetic field, which is zero at the center of the anti-Helmholtz coil 12. The magnetic field strength increases as it moves away from the center. Under the action of the gradient magnetic field, the atomic energy levels will undergo Zeeman splitting. Combined with the action of the cooling light 13 laser, the atoms will be subjected to a force that always points to the center of the magnetic field. Therefore, the atoms in the vacuum chamber 11 will be decelerated and gathered at the center of the magnetic field to form a low-temperature cold atomic cluster, also known as a cold atomic cluster.

[0033] The specific method for performing on-demand connection of quantum bits in an atomic array using the on-demand connection device for quantum bits in an atomic array of the present application is as follows:

[0034] First, a magneto-optical trap system 1 is used to generate a low-temperature and low-speed cold atomic cluster;

[0035] Then, the first dipole light 81 is transmitted to the first fiber coupling frame 811 through the optical fiber, and the light output by the first fiber coupling frame 811 is transmitted to the spatial light modulator 2, and then transmitted to the beam combiner 3 after being reflected by the spatial light modulator 2. Most of the light is transmitted through the beam combiner 3, and then transmitted through the first filter 41, and then focused by the first strong focusing lens 51 to form a two-dimensional dipole trap array, and the focus coincides with the cold atomic cluster in the magneto-optical trap system 1, as shown in FIG. Figure 2 As shown. The focus of the two-dimensional dipole trap array coincides with the center of the cold atomic cluster, so the two-dimensional dipole trap array can be used to trap and load single atoms to form a quantum bit array;

[0036] Then turn on the first quantized magnetic field coil 61 and the second quantized magnetic field coil 62, where the quantized magnetic field is generated by a pair of Helmholtz coils, and the direction of the magnetic field is along the propagation direction of the first dipole light 81. Assuming that the magnitude of the quantized magnetic field is B, the quantized magnetic field can cause Zeeman splitting of the atomic energy level.

[0037] A moving trap is generated by another position-controlled dipole light beam, i.e., a second dipole light 82, and moves in the two-dimensional dipole trap array to transfer atoms in a single trap in the two-dimensional dipole trap array and move with the moving trap. Specifically, the second dipole light 82 is transmitted to the second fiber coupling frame 822 through the optical fiber, and the light output by the second fiber coupling frame 822 is diffracted by the acousto-optic deflector 9 and then incident on the beam combiner 3. The diffracted light is incident on the beam combiner 3, where part of the light is reflected. The light reflected by the beam combiner 3 then passes through the first filter 41 and is transmitted. After transmission, the light is focused by the first strong focusing lens 51 and focuses on the focal plane of the two-dimensional dipole trap array. The frequency of the radio frequency signal of the acousto-optic deflector 9 is changed to achieve a shift in the incident angle of the light spot, and the focused light spot of the second dipole light 82 is moved on the focal plane of the two-dimensional dipole trap array, and the moving range can cover the range of the entire two-dimensional dipole trap array. The focused light spot of the second dipole light 82 is the moving trap.

[0038] Among them, when the mobile well and a single well in the two-dimensional dipole well array overlap, the well depth at this time can be considered to be the superposition of the well depths of the two wells. When the mobile well and the single well in the two-dimensional dipole well array are separated from the overlapping state, assuming that the well depth of the mobile well is higher, then the atoms in the single well in the two-dimensional dipole well array will be transferred out by the mobile well and move with the mobile well. By optimizing the well depth of the mobile well, the efficiency of the atoms being transferred out can be maximized. This application has found through experimental research that when the well depth of the mobile well, that is, the power, is twice the power of a single well in the two-dimensional dipole well array, the transfer efficiency reaches a maximum value of 99%, such as Figure 3 As shown, Figure 3 The middle horizontal axis shows the ratio of the mobile trap power to the stationary trap power, where the two-dimensional dipole trap array is the stationary trap. Specifically, the fidelity of the atoms in the transfer process was measured to be 99% through quantum state tomography, which means that the transfer process did not affect the internal state of the atoms, laying the foundation for the subsequent transfer of entangled atoms.

[0039] Then it is necessary to find the magic light intensity conditions of the two-dimensional dipole trap array and the mobile trap and make both the two-dimensional dipole trap array and the mobile trap under the magic light intensity conditions. In a general linearly polarized dipole trap, the differential light frequency shift caused by the dipole light felt by the atoms is proportional to the well depth, and the coherence time of the atomic ground state is mainly limited by the differential light frequency shift caused by the dipole trap. The longer the coherence time, the better the state of the quantum bit, so it is necessary to suppress any factors that may cause decoherence as much as possible. In the circularly polarized trap, the present application found through experimental research that the differential light frequency shift and the power of the two-dimensional dipole trap array (ie, the well depth) are in a parabolic relationship, such as Figure 4 As shown, Figure 4 The frequency shown on the vertical axis is the differential optical frequency shift. At the lowest point of the parabola, the first-order partial derivative of the differential optical frequency shift with respect to the well depth is zero, greatly reducing the sensitivity of the differential optical frequency shift. The dipole well corresponding to this lowest point of the parabola is the magic light intensity dipole well. The application of the magic light intensity well can significantly improve the coherence time of atomic qubits, from the initial milliseconds to seconds. Because the size of the magic light intensity point is proportional to the quantized magnetic field B, a magic light intensity point can be obtained under different quantized magnetic field conditions. However, the intensities of the magic light intensity point vary, and the ultimate coherence time also varies. This is because the different magic light intensities lead to different temperatures of the atoms in the dipole well. The higher the temperature, the shorter the atomic coherence time. Therefore, comprehensive considerations are required when selecting the magic light intensity point.

[0040] Assuming that the power of the two-dimensional dipole trap array that does not affect the atomic temperature is P1, the power points of twice P1 required by the mobile trap and three times P1 when the mobile trap and a single trap in the two-dimensional dipole trap array are in the overlap state need to be near the lowest point of the parabola. When the quantized magnetic field is 3.46 Gauss, Figure 4The relationship between the differential optical frequency shift and the dipole trap power is shown in Figure 1. Figure 4 It can be seen that there is a parabolic relationship between the differential optical frequency shift and the dipole trap power. The parabola fitting results in a quantized magnetic field of 360μW. At the lowest point of the parabola curve, the magic light intensity is 360μW. The power P1 of the two-dimensional dipole trap array that does not affect the atomic temperature is selected as 120μW. Figure 4 It can be seen that when P1 = 120 μW, 2P1 = 240 μW and 3P1 = 360 μW, all three points being near the lowest point of the parabola. Therefore, all three points are at or near the magic intensity. Therefore, the power controlling the two-dimensional dipole trap array is 120 μW, and the power controlling the mobile trap is 240 μW. At this point, both the two-dimensional dipole trap array and the mobile trap are at the magic intensity.

[0041] After measurement, when both the two-dimensional dipole trap array and the mobile trap are under magic light intensity conditions, that is, the power P1 of the two-dimensional dipole trap array is 120μW, and the power P2 of the mobile trap is 240μW, the atomic ground state coherence time is about 300ms when there is a transfer process, and the atomic ground state coherence time is also about 300ms when there is no transfer, proving that the transfer process does not affect the coherence time of the atoms.

[0042] After optimizing the transfer efficiency of the mobile trap, the power of the two-dimensional dipole trap array and the power parameters of the mobile trap are fixed. Then, the radio frequency coordinates corresponding to each grid point in the two-dimensional dipole trap array are calibrated so that the mobile trap traverses the position of each trap in the two-dimensional dipole trap array, and then the radio frequency waveform of the acousto-optic deflector 9 is set to realize the transfer of atoms between the traps in the two-dimensional dipole trap array. Assume that the radio frequency coordinates corresponding to the first trap are (90MHz, 92MHz) and the radio frequency coordinates corresponding to the second trap are (93MHz, 95.5MHz). Then the radio frequency waveform of the mobile trap is set to (90→93, 92→95.5), where → represents frequency sweep, so that the mobile trap can be transferred between the two traps. The specific transfer path of the mobile trap needs to be determined according to the actual situation of the array arrangement.

[0043] After calibrating the RF coordinates corresponding to each grid point in the two-dimensional dipole trap array, the mobile trap can be combined to realize the fast, efficient and coherent transfer of quantum bits between the two array grid points, so as to achieve the on-demand connection requirements of the quantum bits in the array. Specifically: first, atoms are loaded into the two-dimensional dipole trap array through a random loading process, and then fluorescence imaging is used to determine which dipole traps are loaded with single atoms. Generally, the probability of each trap transferring an atom is 50%. Then, a mobile trap is used to move a distant atom to a close distance, such as Figure 5As shown in the figure, when the distance between the two atoms meets the requirements of Rydberg blockade, a non-resonant modulated pulse scheme can be used to simultaneously apply Rydberg excitation light to the two atoms, thereby realizing a two-bit controlled phase gate. After the manipulation of the atoms is completed, the two atoms are in an entangled state of the ground state. At this time, the moved atom is moved back to its original position using a moving trap. At this point, the two atoms are still in an entangled state, but the distance between the two atoms is very large. By moving one of the atoms back and forth quickly, efficiently, and coherently by moving the moving trap, the long-distance atoms are finally connected. That is, there is a strong Rydberg interaction between the two distant atoms, which can achieve entanglement of the two atoms.

[0044] Figure 5 A schematic diagram of on-demand connection of quantum bits in a two-dimensional dipole trap array is given, Figure 5 As can be seen, the long-distance mobile bit is moved by the mobile trap under magic light intensity conditions along the transfer path to the nearest position of the stationary bit, whereupon both are placed in the Rydberg interaction region. At this point, the two bits are entangled through the close-range Rydberg interaction, achieving the purpose of connection. After entanglement is complete, the mobile bit is returned along the original path by the magic light mobile trap, achieving on-demand connection of long-distance qubits in a two-dimensional dipole trap array.

[0045] This application uses a two-dimensional dipole trap array and a mobile trap method under magic light intensity conditions to connect any two atoms in the two-dimensional dipole trap array. The connection method between atoms can be flexibly selected according to the needs of the quantum algorithm to achieve the purpose of on-demand connection.

[0046] Although the implementation scheme of the present application has been disclosed as above, it is not limited to the applications listed in the description and implementation mode. It can be fully applied to various fields suitable for the present application. For those familiar with this field, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present application is not limited to the specific details and illustrations shown and described herein.

Claims

1. A device for connecting quantum bits on demand in an atomic array, characterized in that: include: Magneto-optical trap system, used to generate low-temperature and low-speed cold atomic clusters; A spatial light modulator, a beam combiner, a first optical filter, a first strong focusing lens, and a first quantized magnetic field coil are sequentially arranged on one side of the magneto-optical trap system and along the central axis of the magneto-optical trap system; and a second quantized magnetic field coil, a second strong focusing lens, a second optical filter, and a CCD camera are sequentially arranged on the other side of the magneto-optical trap system and along the central axis of the magneto-optical trap system; Among them, a beam of dipole light is transmitted to the spatial light modulator, reflected by the spatial light modulator and transmitted to the beam combiner, then transmitted through the first filter, and then focused by the first strong focusing lens to form a two-dimensional dipole trap array, and the focus coincides with the cold atomic cluster in the magneto-optical trap system; another beam of dipole light is diffracted by the acousto-optic deflector and then incident on the beam combiner, the light reflected by the beam combiner passes through the first filter and is transmitted, and the light after transmission is focused by the first strong focusing lens and the focus falls on the focal plane of the two-dimensional dipole trap array; the first Rydberg excitation light is reflected by the first filter and focused by the first strong focusing lens and the focus falls on the focal plane of the two-dimensional dipole trap array; After being reflected by the second filter, the second Rydberg excitation light is focused by the second strong focusing lens, and the focus falls on the focal plane of the two-dimensional dipole well array in reverse.

2. The device for on-demand connection of quantum bits in an atomic array according to claim 1, characterized in that: The magneto-optical trap system includes a vacuum chamber, with a pair of anti-Helmholtz coils provided at the center of the vacuum chamber to form a gradient magnetic field with increasing magnetic field strength from the center of the anti-Helmholtz coils toward the outside; three pairs of cooling lights are provided in the vacuum chamber to subject atoms to radiation pressure along the propagation direction of the cooling lights, and to cause the atoms in the vacuum chamber to form low-temperature, low-speed cold atomic clusters that gather at the center of the gradient magnetic field.

3. The device for on-demand connection of quantum bits in an atomic array according to claim 2, characterized in that: The three pairs of cooling lights are lasers with a wavelength of 780 nm that propagate in opposite directions. The cooling lights cause the atoms to be subjected to radiation pressure along the propagation direction of the cooling lights, thereby slowing down the atoms and forming optical clumps.

4. The device for on-demand connection of quantum bits in an atomic array according to claim 3, characterized in that: The one dipole light beam is transmitted to a first fiber coupling frame via an optical fiber, and the light output by the first fiber coupling frame is transmitted to the spatial light modulator; the other dipole light beam is transmitted to a second fiber coupling frame via an optical fiber, and the light output by the second fiber coupling frame is diffracted by the acousto-optic deflector and then incident on the beam combiner. The incident angle of the light spot is shifted by changing the frequency of the radio frequency signal of the acousto-optic deflector, and the movable trap is moved on the focal plane of the two-dimensional dipole trap array.

5. The device for on-demand connection of quantum bits in an atomic array according to claim 4, characterized in that: The spatial light modulator is connected to a host, and a GS algorithm is run on the host to generate a phase diagram, so that the spatial light modulator modulates the phase of the beam of dipole light, and forms a two-dimensional dipole well array after the beam of dipole light is strongly focused by the first strong focusing lens.

6. A method for on-demand connection of quantum bits in an atomic array based on the device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Use the magneto-optical trap system to obtain low-temperature and low-speed cold atomic clusters; A two-dimensional dipole well array is formed by strongly focusing a beam of dipole light, and the focus of the two-dimensional dipole well array coincides with the center of the cold atomic cluster to load atoms to form a quantum bit array; generating a moving well by another position-controlled dipole light beam and moving the moving well in the two-dimensional dipole well array, so as to transfer atoms from a single well in the two-dimensional dipole well array and move the atoms along with the moving well; In which, the two-dimensional dipole trap array and the mobile trap are both under magic light intensity conditions. When the mobile trap moves the atoms in a single trap of the two-dimensional dipole trap array to a distance between the atoms in another single trap that meets the Rydberg blockade requirement, the Rydberg excitation light is simultaneously applied to the two atoms to realize a two-bit controlled phase gate; and then the moved atoms are moved back to their original positions through the mobile trap to realize long-distance on-demand connection of any two atoms in the two-dimensional dipole trap array.

7. The method for on-demand connection of quantum bits in an atomic array according to claim 6, characterized in that: The power of the mobile trap is twice the power of the two-dimensional dipole trap array.

8. The method for on-demand connection of quantum bits in an atomic array according to claim 7, characterized in that: The dipole light generated by the moving trap is focused on the two-dimensional dipole trap array after passing through the acousto-optic deflector, and the angle of the emitted light is changed by changing the frequency of the radio frequency signal input to the acousto-optic deflector, so that the light can move in the two-dimensional dipole trap array.

9. The method for on-demand connection of quantum bits in an atomic array according to claim 8, characterized in that: The radio frequency coordinates corresponding to each grid point in the two-dimensional dipole trap array are calibrated, and the radio frequency waveform of the mobile trap is set so that the mobile trap traverses the position of each trap in the two-dimensional dipole trap array.

10. The method for on-demand connection of quantum bits in an atomic array according to claim 9, characterized in that: Atoms are loaded into the two-dimensional dipole trap array through a random loading process, and then fluorescence imaging is used to determine whether atoms are loaded in each single trap of the two-dimensional dipole trap array.

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